|
Current COPD Treatments
Compared with discussion of asthma therapy, the topic of COPD management has been
relatively neglected in the past. That is changing, however. Major guidelines for treating
COPD have been issued in recent years by the American Thoracic Society,[9] British
Thoracic Society,[21] and European Respiratory Society.[22] More recently, there has been a
major statement on COPD from the scientific committee of the Global Initiative for
Chronic Obstructive Lung Disease, a joint project of the National Heart, Lung, and Blood
Institute and the World Health Organization.[19]
The treatment objectives for COPD include slowing the accelerated decline in lung
function; relieving symptoms, such as shortness of breath and cough; improving daily
lung function; decreasing exacerbations; and improving quality of life.[7,19]
The most important step in treating COPD is to encourage smoking cessation. There is a
direct relationship between smoking and accelerated loss of lung function in susceptible
persons. Smoking cessation has been shown to stop this accelerated loss, so that decline
in lung function returns to the normal rate seen with aging.[23]
Most experts advocate early detection of COPD and active intervention to stop smoking.
Smoking cessation has been shown to halt the accelerated loss of lung function associated
with COPD. It also stops the loss of lung function in younger patients with relatively
mild disease.[4] However, any COPD patient can benefit from smoking cessation, no matter how advanced the disease.
Medications
Medications can be used to relieve symptoms of COPD, particularly shortness of breath,
and to treat respiratory tract infections that can worsen COPD.[19] Currently available
medications that are helpful in treating COPD include bronchodilators and
corticosteroids. Antibiotics are useful in treating exacerbations caused by bacterial
infections. No medications have been found to cure the disease or reverse the loss of
lung function caused by smoking.[8]
Medications of different classes have been found to be useful in treating COPD and can
be used in combination. The overall approach to managing stable COPD involves a
stepwise increase in treatment, depending on the severity of the disease.[19]
Bronchodilators
Bronchodilators are a class of medications that relax the muscles around the bronchi to
allow easier breathing. They are typically indicated for the relief of bronchospasm,
which are contractions of the smooth muscle in the walls of the bronchi and bronchioles
that cause the airways to constrict or narrow.[8] Anticholinergic bronchodilators fall into
this class of COPD medications, as do short-acting beta2-agonists, long-acting beta2-
agonists, methylxanthines (e.g., theophylline), and a combination of an anticholinergic
bronchodilator and a short-acting beta2-agonist.
All major guidelines for COPD management recommend beginning treatment with
aerosol bronchodilators, which are inhaled directly into the lungs and have few side
effects.[18,19,21,22]
Anticholinergic bronchodilators
In response to irritants such as cigarette smoke, the body produces a chemical
"messenger" called acetylcholine that induces the airways to constrict. Anticholinergics
are the only medications that act by blocking acetylcholine, thereby relaxing the muscle
tissue and keeping the airways open.[24] Anticholinergic medications work via part of the
parasympathetic nervous system, which controls airway size.
In addition to helping COPD patients take fuller breaths,[24] maintenance use of
anticholinergic medication may also help lower the incidence of acute exacerbations in
COPD patients.[25]
The American Thoracic Society, a leading medical authority on respiratory illnesses,
recommends anticholinergics as the first line of maintenance therapy for patients with
daily COPD symptoms.[9] The Global Initiative for Chronic Obstructive Lung Disease
also recognizes anticholinergics as an important treatment for COPD.[19]
Anticholinergics are most often administered through metered-dose inhalers, or
"puffers," as they are commonly called. The effects of the medication generally last from
four to six hours, so physicians typically prescribe use four times a day.[9] Inhaled
anticholinergics are minimally absorbed, resulting in relatively few side effects. Some
common side effects of ipratropium bromide, an inhaled anticholinergic therapy, include
cough and nervousness.[24]
Anticholinergic bronchodilators, as a class, are the number one prescribed bronchodilator
used in the treatment of COPD.[26] Currently, the leading anticholinergic medication
prescribed by physicians is ipratropium bromide. It is sold alone under the brand name
ATROVENT, Inhalation Aerosol or in combination with albuterol sulfate under the
brand name COMBIVENT, Inhalation Aerosol.
Beta2-agonists
Beta2-agonists work via part of the nervous system that controls muscle tissue around the
airways. They work by stimulating receptors in the sympathetic nervous system, leading
to dilation of air passages.[8] Two types of beta2-agonists are available: short-acting beta-
agonists and long-acting beta-agonists.
Short-acting beta2-agonists
These medications are recommended by the American Thoracic Society for patients with
COPD who experience intermittent symptoms.[9] They are also used as a "rescue"
medication to fend off an impending attack of shortness of breath. Short-acting beta2-
agonists are typically prescribed along with anticholinergics to open up the airways of
COPD patients with continuing symptoms.[9] The short-acting beta2-agonist most
commonly prescribed by physicians is albuterol.[26] In clinical studies, the most common
side effects of albuterol included tremor, nausea, tachycardia, palpitations and
nervousness.[27]
Long-acting beta-agonists
These bronchodilators are taken twice a day and, like short-acting beta-agonists, work via
part of the nervous system that controls muscle tissue around the airways. They are
recognized as a treatment for COPD by the Global Initiative for Chronic Obstructive
Lung Disease.[19]
Long-acting beta-agonists are often prescribed for nighttime breathing problems because
they provide up to 12 hours of relief.[19] Patients using long-acting beta-agonists need to
be reminded to continue using their short-acting beta-agonist for "rescue" therapy,
because long-acting beta-agonists do not work as quickly and are indicated for use only
twice a day.[28] The most common side effects seen with use of long-acting beta-agonists
by patients with COPD include headache, upper respiratory tract infection,
nasopharyngitis and cough.[27]
Combination bronchodilators
The combination of an anticholinergic and short-acting beta2-agonist works via the part
of the nervous system that controls airway size, as well as the part that controls muscle
tissue around the airways. Increased efficacy is seen with this combination agent over
the individual components, without an increase in side effects.[29] The most common side
effects include bronchitis, upper respiratory tract infection and headache. [30]
Theophylline
Another bronchodilator used in the treatment of COPD is theophylline, which is taken
orally. Theophylline affects many parts of the body, including muscle tissue and the
heart. It works by opening up the airways, increasing muscle endurance, and decreasing
muscle fatigue. At one time, theophylline was the most widely prescribed COPD
medication, but it has lost favor because of side effects. However, theophylline may have
benefits that go beyond bronchodilation, and it is still an important part of COPD
management.[9]
Theophylline is taken orally once or twice a day, so it may be particularly valuable for
noncompliant patients who cannot optimally use aerosol therapy. The dosage should be
adjusted to reach a therapeutic serum level, so blood levels should be monitored.[9]
However, some patients experience side effects even at low serum levels. The most
common side effects seen are nausea, vomiting, headache and insomnia.[31]
Corticosteroids
Currently, inhaled corticosteroids are not indicated for the treatment of COPD. They are the cornerstone of asthma therapy, but have a limited role in the maintenance of lung function in patients with COPD. Only about 10 percent of patients
with COPD show a significant improvement in lung function when treated with
corticosteroids.[32] The reason is that different mediators cause inflammation in asthma
and COPD.[32] The mediators that cause inflammation in COPD have only limited
responsiveness to corticosteroids, while those mediators responsible for inflammation in
asthma are dramatically affected by inhaled corticosteroids.[32]
Surveys of clinicians' prescribing habits, however, have shown little difference in the use
of inhaled corticosteroids for asthma patients and for COPD patients.[33],34] Guidelines for
the treatment of COPD suggest that because inhaled corticosteroids play only a minor
role in the maintenance treatment of COPD and may produce systemic side effects, they
should be reserved for patients whose symptoms are not optimally controlled with
bronchodilators. This subgroup of patients should receive inhaled or oral corticosteroids
for a trial period. If a significant objective clinical response is not achieved,
corticosteroids should be discontinued. When a benefit is observed with oral
corticosteroids, the dose should be tapered to the lowest possible dose. At that point, a
trial of an inhaled corticosteroid should be initiated.[19,21] The most common side effects of
inhaled corticosteroids include upper respiratory infection, headache and pharyngitis.
Antibiotics
Antibiotics may be given to patients with COPD for acute bacterial infections of the
respiratory tract, including sinusitis, acute bronchitis and some types of pneumonia.[8]
Antibiotics are also used to treat exacerbations when symptoms of infection are present,
such as fever, increased cough and sputum changes.[9]
|
